University of Edinburgh, 04-09-2014
Author: Luca Foresta

This file is a guide for reading L2Swath binary files. Once loaded the file as 'float32', the last two bytes give information on how to unpack the single fields. Namely:
last byte    = rec_size  (amount of waveforms in file)
last byte -1 = meas_size (amount of lon/lat/elev measurements in file)

The fields in the binary file are saved in the following order (their size in bytes is given in square brackets):

1. [meas_size]      Longitude
2. [meas_size]      Latitude
3. [meas_size]      Elevation
4. [meas_size]      Waveform number of measurement (identifies the original waveform number of the given measurement)
5. [512*rec_size]   Power matrix 
6. [512*rec_size]   Phase matrix (unwrapped, masked)
7. [512*rec_size]   Coherence matrix
8. [rec_size]       Linear phase fit error
9. [rec_size]       Quadratic phase fit error


Example code to read the files is given here:

% fid2 = fopen(filename);
% data = fread(fid2,'float32');
% fclose(fid2);
% 
% % reconstruct fields
% 
% record_size = data(end);
% measurement_size = data(end-1);
% 
% longitude = data(1:measurement_size);
% latitude = data(measurement_size+1:measurement_size*2);
% elevation = data(measurement_size*2+1:measurement_size*3);
% waveform_number = data(measurement_size*3+1:measurement_size*4);
% 
% marker1 = measurement_size*4 +1;
% datastep = record_size*512;
% power_data = data(marker1:marker1+datastep-1);
% power_data = reshape(power_data, 512, record_size);
% phase_data = data(marker1+datastep:marker1+datastep*2-1);
% phase_data = reshape(phase_data, 512, record_size);
% coh_data = data(marker1+datastep*2:marker1+datastep*3-1);
% coh_data = reshape(coh_data, 512, record_size);
% 
% marker2 = marker1+datastep*3 + 1;
% phaseLin_err = data(marker2:marker2+record_size);
% phaseQuad_err = data(marker2+1+record_size:marker2+record_size*2);